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Neurotransmitters as food supplements: the effects of GABA on brain and behavior.

Boonstra E, de Kleijn R, Colzato LS, Alkemade A, Forstmann BU, Nieuwenhuis S - Front Psychol (2015)

Bottom Line: Although many consumers claim that they experience benefits from the use of these products, it is unclear whether these supplements confer benefits beyond a placebo effect.We suggest that any veridical effects of GABA food supplements on brain and cognition might be exerted through BBB passage or, more indirectly, via an effect on the enteric nervous system.We conclude that the mechanism of action of GABA food supplements is far from clear, and that further work is needed to establish the behavioral effects of GABA.

View Article: PubMed Central - PubMed

Affiliation: Cognitive Psychology Unit, Institute of Psychology, Leiden University , Leiden, Leiden ; Leiden Institute for Brain and Cognition, Leiden University , Leiden, Leiden.

ABSTRACT
Gamma-aminobutyric acid (GABA) is the main inhibitory neurotransmitter in the human cortex. The food supplement version of GABA is widely available online. Although many consumers claim that they experience benefits from the use of these products, it is unclear whether these supplements confer benefits beyond a placebo effect. Currently, the mechanism of action behind these products is unknown. It has long been thought that GABA is unable to cross the blood-brain barrier (BBB), but the studies that have assessed this issue are often contradictory and range widely in their employed methods. Accordingly, future research needs to establish the effects of oral GABA administration on GABA levels in the human brain, for example using magnetic resonance spectroscopy. There is some evidence in favor of a calming effect of GABA food supplements, but most of this evidence was reported by researchers with a potential conflict of interest. We suggest that any veridical effects of GABA food supplements on brain and cognition might be exerted through BBB passage or, more indirectly, via an effect on the enteric nervous system. We conclude that the mechanism of action of GABA food supplements is far from clear, and that further work is needed to establish the behavioral effects of GABA.

No MeSH data available.


GABA’s chemical structure.
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Figure 2: GABA’s chemical structure.

Mentions: With regards to the first factor, not every study has employed the same chemical compound. One study administered 4-amino-3-hydroxybutyric acid (Kuriyama and Sze, 1971). Although this compound has a different chemical structure than GABA (i.e., an extra OH group), this study is often cited as providing evidence for GABA’s inability to cross the BBB. In view of the role that simple chemical properties play in BBB permeation, it might be problematic to generalize findings with different chemical compounds to GABA as it is found in the central nervous system and its food supplement version. All other studies that have reported evidence for or against GABA’s BBB permeability either administered radioactively labeled GABA (which is chemically identical to GABA, see Figure 2), or did not further specify the kind of GABA they used.


Neurotransmitters as food supplements: the effects of GABA on brain and behavior.

Boonstra E, de Kleijn R, Colzato LS, Alkemade A, Forstmann BU, Nieuwenhuis S - Front Psychol (2015)

GABA’s chemical structure.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4594160&req=5

Figure 2: GABA’s chemical structure.
Mentions: With regards to the first factor, not every study has employed the same chemical compound. One study administered 4-amino-3-hydroxybutyric acid (Kuriyama and Sze, 1971). Although this compound has a different chemical structure than GABA (i.e., an extra OH group), this study is often cited as providing evidence for GABA’s inability to cross the BBB. In view of the role that simple chemical properties play in BBB permeation, it might be problematic to generalize findings with different chemical compounds to GABA as it is found in the central nervous system and its food supplement version. All other studies that have reported evidence for or against GABA’s BBB permeability either administered radioactively labeled GABA (which is chemically identical to GABA, see Figure 2), or did not further specify the kind of GABA they used.

Bottom Line: Although many consumers claim that they experience benefits from the use of these products, it is unclear whether these supplements confer benefits beyond a placebo effect.We suggest that any veridical effects of GABA food supplements on brain and cognition might be exerted through BBB passage or, more indirectly, via an effect on the enteric nervous system.We conclude that the mechanism of action of GABA food supplements is far from clear, and that further work is needed to establish the behavioral effects of GABA.

View Article: PubMed Central - PubMed

Affiliation: Cognitive Psychology Unit, Institute of Psychology, Leiden University , Leiden, Leiden ; Leiden Institute for Brain and Cognition, Leiden University , Leiden, Leiden.

ABSTRACT
Gamma-aminobutyric acid (GABA) is the main inhibitory neurotransmitter in the human cortex. The food supplement version of GABA is widely available online. Although many consumers claim that they experience benefits from the use of these products, it is unclear whether these supplements confer benefits beyond a placebo effect. Currently, the mechanism of action behind these products is unknown. It has long been thought that GABA is unable to cross the blood-brain barrier (BBB), but the studies that have assessed this issue are often contradictory and range widely in their employed methods. Accordingly, future research needs to establish the effects of oral GABA administration on GABA levels in the human brain, for example using magnetic resonance spectroscopy. There is some evidence in favor of a calming effect of GABA food supplements, but most of this evidence was reported by researchers with a potential conflict of interest. We suggest that any veridical effects of GABA food supplements on brain and cognition might be exerted through BBB passage or, more indirectly, via an effect on the enteric nervous system. We conclude that the mechanism of action of GABA food supplements is far from clear, and that further work is needed to establish the behavioral effects of GABA.

No MeSH data available.